Basic Genetics and Heredity Flashcards
genetic material (DNA or RNA) packaged with proteins
chromosomes
segment of DNA that contains info. to make one protein
gene
different versions of a gene resulting in contrasting effect on a characteristic
eg: tallness or shortness
allele
mendel’s principles of heredity
first hypothesis - second hypothesis (principle of dominance or recesiveness) - third hypothesis (law of segregation) - fourth hypothesis (law of independent assortment)
inherited characteristics are controlled by factors that occur in pairs
first hypothesis
one allele (dominant trait) in a pair may mask the other (recessive trait) and that dominant trait PREVENTS the recessive trait from having an effect
principle of dominance and recesiveness
alleles for one gene segregate during gamete formation
during gamete formation, the alleles for each gene segregate from each other such that EACH GAMETE FORMED carries only ONE allele for EACH gene
law of segregation
primarily because it has no fixed pattern
genes of different trait assort independent of each other during gamete formation
law of independent assortment
alleles possessed by an indiv. for a particular gene
genetic make-up of gene shows the alleles present
genotype (TT - homozygous tall)
observable characteristic of the indiv. with respect to that gene
external appearance dictated by genotype
phenotype (tall)
individual with identical alleles for a gene
containing same types of alleles
also called PURE BREEDING
homozygous
individual with 2 different alleles for a gene
heterogeneous
used to determine the various combination of gene
determine genotype and phenotype of offspring in a parent test cross
punnett square method
non-mendelian genetics
incomplete dominance - co-dominance - multiple alleles
phenotype of the heterozygote is a 3rd trait that is DISTINCT and DIFFERENT from phenotypes of the homozygotes for the two alleles
eg: white and red rose = pink rose
incomplete dominance
neither of the allele is masked, both is expressed in the organism
the phenotype of the heterozygote is a combination of the two phenotypes
cow with red hair and cow with white hair = offspring with bot red and white hair
co-dominance
a gene still contains two alleles but there are more than two types of alleles with different degrees of dominance
eg: human blood
multiple alleles
a single gene affects different phenotypes
eg: there is only one gene that determines pea flower color and pea seed color
pleiotropy
a single phenotype is affected by two different genes
one gene depends on another gene for it to be expressed
eg: two genes need to have a dominant allele for a Labrador to have a yellow fur
epistasis
a gene expression isnt limited to 2 diff. traits but instead several degrees of the trait
two or more genes contribute to the phenotype
eg: skin color isn’t just black or white, but different shades
polygenic inheritance
genes that are found in the 23rd pair of chromosome/sex chromosome
sex-linked traits
females have __ chromosome
XX
males have __ chromosome
XY
diseases that are what type of x-linked:
D-resistant rickets
oral-facial-digital syndrome I
fragile x syndrome
dominant x-linked
diseases that are what type of x-linked:
red-green color blindness
hemophilia a and b
duchenne muscular dystrophy
recessive x-linked
if a gene is passed in the Y chromosome, it will be passed only to ____
male offspring
XY
healthy male
XX
healthy female
XᶜY
affected male
XᶜYᶜ
affected female
XᶜX
carrier female
substances that can trigger immune response if foreign to the body
antigens
how many antigens does blood type O have
none
universal donor
blood type o
